Electrical crimps

[Bubbleboy]

Hi all.....im looking ahead and trying to learn as much as I can with regard to my aircraft build. I have been reading up on the crimps for making electrical connections. I attended a forum at Natfly and learnt a lot about what to do and what not to do. I know soldering is a no no.

 

I guess what I need to learn about is what is the acceptable standard with regard to the tooling. I have always used the cheap crimping packs you buy from places like Super Cheap Auto for my car and bike needs but now I know these are not really acceptable in an aircraft. Is there a particular brand of tool and crimp available in Australia that builders use? I have seen some crimping tools over a $100 which I have no problem paying that much but expensive is not always good.

 

Can someone take a minute or two and educate with regard to this please?

 

Scotty i_dunno

 

 

[old man emu]

Scotty,

 

It's against my agreement with Ian to answer your question here as it would appear that I am touting for business. However, I'm sure that if you posted in the Suppliers section, you would get the answer that you need.

 

Old Man Emu

 

 

[Guest ozzie]

spend the money and get a good set. I have a set of 'king chrome' ones. they will not release untill the handels travel to the fully closed position making sure they crimp correctly. the crimp jaws do the three sizes red blue and yellow codes and are interchangable for other applications like bnc radio type connections. ect

 

i have never had a crimp fail with these.

 

 

[Bubbleboy]

Hi Ozzie...thanks for that mate. You dont have the part number by any chance? I saw two models If I recall correctly, by king chrome, and quite a price difference at my local engineering shop. Better make sure im comparing apples to apples.

 

Scotty

 

 

[Guest ozzie]

There is no part number on this set. they were around $65. at bunnies They are good quality around 500g in weight. have blue handles. i'll post a photo tonite if you need

 

ozzie

 

 

[Bubbleboy]

Thanks Ozzie...the set I was looking at was around the $150 mark! If you say yours do the job, thats even better. Now are all crimps the same or are you better to buy crimps to suit the tool. I know there are the 3 different colours. Would I be naive thinking that all manufacturers adhere to strict sizing? I know at the Cable forum at Natfly they emphasised about Nicopresses. You need all the correct parts for the join to be right. Im wondering if these crimps are the same?

 

Scotty

 

 

[Yenn]

The colours are coding for size. For most aircraft use the red is appropriate, the yellow for heavy cables. No doubt someone here can give the actual sizes for each colour.

 

 

[old man emu]

Don't worry about Nicopress oval sleeves. Their sizes are specific for the size of the cable they are swaging. You'll need a special swaging tool to do this job. It's not worth you while to buy one for just one build. Better to seek the generosity of the homebuilder brotherhood.

 

Looks like a trip to Sydney, maybe.

 

I checked at work today, and the boss said to get your crimper from Bunnings. Buy one with a bit of quality, but you shouldn't have to go much over $50 or so.

 

For cable terminals you'll order things in the MS25036- group.

 

If you have a wire leading to, say, a lamp fitted to a cowl, and you want to be able to remove the cowl easily, you need to make a breakable link. For that you use a knife splice.

 

Ring terminals and knife splices are made by AMP Inc of Harrisburg PA.

 

If my scanner gets fixed tonight, I'll post some data for your infrmation.

 

Old Man Emu

 

 

[Bubbleboy]

Thanks to everyone who has helped educate me here! Love this forum and the plethora of help given freely! I will have a look in Bunnings next time I am in there and see what they have.

 

Old Man Emu...would love any literature you may have. I get a bit anal about wanting to know everything about a process so I can do the best job, gets me in trouble sometimes...lol!

 

I wasnt going to buy a Nicopress tool I was just using it as an example of needing specific parts to get a good join. Your right...I will need to ask around to see if someone has one when that time comes. Im in the SAAA so someone should have one. Wont be for a while at this rate anyway!

 

Thanks again to all

 

Scotty :thumb_up:

 

 

[Guest ozzie]

here is the photo of the set i bought from bunnies for $65. they are very good quality kingchome.

 

I also have a set with orange hanldls i think they are utilux brand but they are set up for fitting BNC type connectors for aerials. i bought these about 20 years ago when i was fitting the car kits for the first bag type mobile phones. these were expensive around $180 back then. The jaws of both are interchangable.

 

As for the lugs, each size is for different wire gauges. Depending on what type of wire cable you are using for your aircraft, use the appropriate lug and material type

 

The certified type wire is stainless for good conductivity and strength and the shielding is of the non flamable non melting type. it is white in colour which makes it a little harder to identify when working with bundels. if you are going to use this type use the little numbered rings that sit just behind the lug to make identifing each individual cable easier. or you can colour code them with different coloured texta markers or different coloured heat shrink.

 

using stainless is expensive but will last a long time and won't fill the cabin with toxic gas if you have a fry up. When passing wire thru the firewall do not use rubber grommets. use gas proof bulkhead screw together type fiitings. you can get neat little stick on fittings now that you can zip tie wire bundels to to save drilling holes for screws ect. Be anal when working with electrical wireing and fuel/oil lines. don't make Boeings mistake, have a bit of excess around bends and where things move or vibrate. A piece of molding on the edge of sheetmetal will also help prevent chafing. use a piece of heat shink at the lug to help prevent the wire breaking due to vibration. if you are going to buy a quality pair of crimpers also buy a good quality pair of strippers that won't damage the wire.

 

hope this dribble helps

 

ozzie

 

 

 

[numptie]

I don't know if they're too expensive but I use Cabac at work. They make a few models of crimp tools (even the basic KTC1 is good) and they also have good quality terminals. You can get them from most electrical supplies, JR Turks, L&H etc, or from Cabac themselves.

 

Bob

 

 

[old man emu]

Here is the information about terminals and splices.

 

OME

 

 

 

 

[sain]

slightly off topic i'm afraid: can anybody tell me why is soldering considered a no-no? I would have thought it would produce a stronger joint, to say nothing of the improved electrical connection over the connectors...

 

 

[Guest ozzie]

the wire will eventually break were the solder ends usually from vibration.

 

 

[Yenn]

I havn't ever seen stainless steel used as a wire in aircraft. Mostly it is copper with either a tin or silver coating. Raw copper wire will fall aart with corrosion in no time, hence the plating. Most of the insulation is either Teflon or Tefzel which do not burn or melt easily and don't give off deadly fumes. For connections that may have to be pulled apart there are multiple wire connectors available from auto electricians, they come in many sizes and look as if they are nylon, They hang together well and the only down side is having to have a special tool to crimp the wires into them. Soldering leaves a solid portion of wire adjacent to a flexible part and over time the wire will move and break, just the same as you can break a piece of 8g wire by bending it backwards and forwards.

 

 

[Thruster87]

[ATTACH]10941.vB[/ATTACH]59250 AMP Crimp Tool

 

T-Head controlled cycle ratchet crimp tool designed for size 22-14 Tyco (AMP) PIDG and Plasti-Grip insulated terminals and splices. I bought a second hand set a couple of years ago for $120.00 on ebay.These are what we use on commerical aircraft Cheers

 

 

 

[Bubbleboy]

I was in the local engineering shop today and there were a pair of Kinchrome wire strippers with a crimper incorporated for $30. Will have a look in Bunnings this week to see what they have.

 

Thanks guys!

 

Scotty :thumb_up:

 

 

[Ding]

Crimper

 

Bought mine at Jacar. Mid range price. Around $40 if memory serves. Best tool I ever bought.

 

Don't use cheap terminals. They are made of harder cheaper metal and you will get varying results. You want consistency.

 

Red terninals are for 3mm wire, blue for 4mm and I think yellow for 6mm. Thats square mm conductor area, not diameter.

 

And no solder. As already noted, causes the wires to break from vibration fatigue. You want the connection as soft as possible.

 

Cheers,

 

Ding.

 

 

[sain]

Thanks for the info on the no-soldering rule guys - much obliged.

 

I'm curious though - isn't the crimp connector body rigid, so wouldn't a properly crimped connector have the same issue with the rigid/flexible joint?

 

 

[Guest davidh10]

Thanks for the info on the no-soldering rule guys - much obliged.I'm curious though - isn't the crimp connector body rigid, so wouldn't a properly crimped connector have the same issue with the rigid/flexible joint?

Not professing to know anything at all about the approved methods of wiring aircraft, but I can see the reasoning...

 

A crimped terminal has some insulation protruding beyond the actual metal crimped section that supports the wire to some degree. If the wire is stranded, then each strand can flex individually a little.

 

When soldering, it is very easy to have the solder wick up the wire under the insulation, where it results in an abrupt transition from solid inflexible to the unsoldered flexible wire. It is sharp transitions, bends and nicks that will be the first area to fail due to fatigue. That is why it is also imperative to use a good stripping tool that does not nick the wire, regardless of the method of termination.

 

By the way, Wicking can be eliminated by clipping a heat sink on the wire just at the edge of the insulation. The solder should also be clipped to expose the flux cores, so that they run first and prevent oxidation. Heat (with the iron) the wire, not the solder, and melt the solder on the heated wire. Ensure the solder is hot enough to flow and that the joint isn't moved while it sets. Either will cause a crystaline joint (dry joint), which can break or develop high resistance, particularly for low voltages.

 

The advantage is that the solid to flexible transition is confined to being immediately adjacent to the joint and does not create a long "lever".

 

This aside, I would have thought (in all innocence) that a correctly soldered joint would be more reliable, provided it was properly supported to prevent bending at the solder transition, such as heatshrink over the join with appropriate length past the actual soldered joint. I know that high reliability soldering is used in satellites.

 

Perhaps crimping is preferred because it is easier to produce an unreliable soldered connection than an unreliable crimped connection. Comments anyone?

 

I'm finding this aspect of the thread interesting, since next weekend I plan on fitting nav lights and strobes to my own aircraft. If people feel it is off-topic, then we could start a new thread?

 

 

[Thruster87]

Thanks for the info on the no-soldering rule guys - much obliged.I'm curious though - isn't the crimp connector body rigid, so wouldn't a properly crimped connector have the same issue with the rigid/flexible joint?

Yep, If the wire is tied down properely it can't flex and thus fatigue [solder joints are still used in commerical aircraft] .Cheers T87